Press



L. SCHULL.

PRESS.

APPLICATION FILED DEC. II, I920.

Patented Nov. 28, 1922..

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L. SCHULL.

PRESS.

APPLICATION man 050.11, 1920.

Patented Nov. 28, 1922..

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wmm-o L. scam.

PRESS. APPLICATION FILED 020.11. 1920.

Patented Nov. 28, 1922..

4 SHEET$-SHEET 3.

U w A L L. SC-HULL.

' PRESS.

APPLICATION F|LED DEC. 11, 1920.

Patented Nov. 28, 1922.;

4 SHEETSSHEET 4.

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Patented Nov. 28, 192.2.

unites star LEOPOLD SQHULL, OF VIENNA, AUSTRIA.

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Application filed December 11, 1920. Serial No. $39,070.

T 0 all whom it may concern Be it known that I, LEOPOLD SGHULL, a citizen of the Austrian Republic, residing at Vienna, Austria, have invented certain new and useful Improvements in Presses (for whichI have filed an application in Austria onMarch 8, 1919), of which the following is a specification.

There are already in use presses operate by eccentric mechanism in which the table is adapted to be raised and lowered by means of a lifting screw. In these construc tions the lifting screw is rotatablyconnected with the tableand engages a nut secured to the standard, whereby the table, which is guided the standard, may be raised or lowered by rotation of the screw in one'direction or the other;

To prevent slip of the table when in a given position of vertical adjustment, the pitch of the screwshould not exceed the angle of friction, i. e., the screw should be self locking. When the pitch of the screw is low, there is experienced the drawback that the speed of raising and lowering the table is relatively low, so that work for the performance of which the slide should be continuously actuated and the table alternately raised and lowered can only be effected with a low speed of rotation of the eccentric.

For this reason the field for such presses is quite limited, because, wrought iron articles which are to be treated while hot re quire to be operated on rapidly. Given the possibility of speeding up the operation of lifting and lowering thetable, and therefore of also a rapid stroke of the slide, such a press can be used for operations which heretofo-recould only be effected by means of power hammers, the operation being effectedmuch more rapidly than was possible screw of high pitch, which screw may be fixedly or rotatably connected Wlthrth table orwithlthe ram.

If thescrew be fixedly connected withthe table or with the ram, the screw engages a nut rotatably mounted in the standard or in the slide, by rotation of which nut in one direction or the other the lifting screw and therewith also the table or theram can be raised and lowered. i c r If the shifting of the table or of the ram is to be effected by actuationof the, lifting screw itself, then in the form in which the table is shiftable the lifting screw, which is secured against movement in axial direction, engages a female thread in the table and its head engages a bearing in the standard. In the form inwhich the ram is shiftable the lifting screw engages a female thread in the slide and its head engages a bearing in the ram. X 1

l Vith the employment of a lifting screw of high pitch (having say three threads) and of a manually or motor driven actuating mechanism (with or without a transmission train) for the nut or the lifting screw. the raising and lowering ofthe table can be effected very rapidly. As, however, a screw of high pitch is not self-locking, there is the risk that the pressure transmitted by the table or by the ramfto the lifting screw may in the first form tend .torotate the nut and in the second form tend to rotate the lifting screw, so that the table or the ram would yield. or slip under the working pressure. In order to prevent slip of the table or the ram, the surface of the nut or of the head .of the lifting screw engagthe bearing is ofsuch contour and extent. that the working pressure transmitted by the table or by the ram through the screw to the nut or to the head of the screw will produce afriction moment which prevents notation of the nut or of thehead of the screw... This friction diminishes only when the working pressure falls off, that is during the upward movement of the slide, and during this time the table or the ram can be readily and rapidly shifted to the desired elevation by operation of the-actuating mechanism.

Four embodiments of the invention are illustrated in the accompanying drawing in which Fig. 1 shows a press operable by eccentric mechanism with a lifting screw fixedlyconnected to. a table adapted to be raised andlowered. Fig. 2 shows a press with a screw-thread; connection between the table and the lifting screw. Fig. 3. shows a press with aram adapted to be raised and lowered and having a fixed connection known manner to effect vertical reciproca-,

tion of the slide 3. The table 1, like the slide 3, is guided vertically in the standard and is fixedly connected with a screw having a thread making a sharp angle with its axis and engaging a nut 6. The nut is rotatably mounted in the standard, and its under surface, which is partly coned, engages a bearing surface provided on the standard. The nut is peripherally toothed at 8, the teeth being engageable by a rack 9, guided in the standard and operable by means of toothed gearing from the handwheellO, so that the nutmay be rotated in one direction or the other. Secured to the lower end of the screw 5 is a spindle 11 fitted with two stop-collars 12, 1 3 adaptedon the raising and lowering of the screw to engage astop 1 1- secured to the standard and thereby to limit the vertical movement of the screw 5 and of the table 4, as is desirable for many operations where exactitude is required. These collars 12 and 13 may be made adjustable by any well-known means not illustrated in the drawings as my invention is not directed to this feature considered in and of itself.

The eccentricity of the driver for the slide may be relatively slight. The number of strokes of the slide per minute may be as large as desired. By controlling the hand wheel 10 the table can be rapidly caused to approach the reciprocating slide and retracted therefrom, so that operations can be performed such as are performed by means of a steam hammer or'other power hammer, with this difference, namely, that there is no" impact on the work (which may be pressed between dies) disposed between the table and the tap, but only the gradual pressure experienced with a press operated by an eccentric. Unlike a power hammer, the press. operates silently.

' The turnin movement exercised on the nut by the screw action during the pressing operation is directly taken up by the friction of the nut working on the bearing surface, so. that thereis notrequired' or the nut a bearing surface greater than is commensurate with the 2 dimensions otherwise re quired for the nut; As a precaution however, the bearing surface for the nut may be wholly or in part conical, as indicated in 1, in orderto increase the friction moment. Obviously the conicity should not be such as to cause the nut to be locked in its bearing, as otherwise it would not be rotated immediately on the falling off of the .working pressure. The rotation of the nut may be effected by a motor and the reversal of the rotation may be effected either manually or by automatic mechanism.

The weight of the table and of the screw. and, if desired, also of the nut, may be balanced if desired by any well-known means which are not illustrated in the drawing as my invention is not directed to this feature, considered in and of itself.

Fig. 2 shows a variant in which the vertically movable table a is internally threaded for engagement by aliftingscrew 5 ofhigh pit-ch; Fixedly connected with the screw 5 is a worm-wheel 15 rotatable in. one direction or the other together with the screw by operation of the hand-wheel 16 acting through the worm 18 mounted in a bracket arm 17 of the standard, whereby the table 4 is adapted to be raised and lowered. The

screw head 20 is coned as at 19 to fitafemale conical bearing provided therefor in 413116 standard, and depending from the head 20' In the embodiment shown in: Fig 2 the 1:

turning moment transmitted to the screw during the pressing operation is takenup by'the' conical bearing surface 19 of the head 20. i

3 shows a variant including a ram 23 adapted to be raised and lowered. The lifting screw '24 is fixedly connected with the ram and engages a rotatable nut 26 having a coned surface 25 fitted to a bearing in the slide 3'. Fixedly connected with the nut 26 is a worm wheel 27 rotatable together with the nut by operation of a hand-wheel 32 acting through a worm 31 on a shaft 30 mounted in bearing brackets 28, '29on the slide. By rotation of the nut the ram is the lifting screw 3 1 is rotatable together with the lifting screw by means of a worm 38' mounted in brackets 36, 37 andv operable by a hand-wheel 39. The conical surface 40 of the head 11 of the lifting screw engages 'a female conical bearing in the ram The turning moment transmittedto the screw during the'pressing operation is, as in the preceding examples, takenup by the friction moment of the head 41 of the screw working in the conicalbealring, so that slip of the ram is prevented,

I claim 2- 1. In mechanism for operating a movable member of a press, a screw having a thread of such high pitch that it is not self-locking when axial pressure is applied thereto, said screw being associated with a member for causing axial movement thereof and means associated with the said screw and permitting the free axial movement thereof when no axial pressure is applied thereto, said means operating to hinder the movement of said screw when the working pressure is applied to the said movable member.

2. In mechanism for operating a movable member of a press, a screw associated with a member adapted to cause the axial movement thereof, the said screw being of such high pitch that it is not self-locking when the working axial pressure is applied thereto the member for operating the said screw having a conical bearing surface, the friction of which is adapted to restrain any axial movement of the said screw when the working pressure is applied thereto.

3. In mechanism for operating a movable member of a press a screw fixedly secured to the said movable member, a revoluble nut associated with the said screw and adapted to cause the axial movement thereof, the said screw being of such high pitch that it is not self-locking, the said nut having a conical bearing surface, the friction of which is adapted to hinder the revolution thereof when the working pressure is applied to the said movable member.

In testimony whereof I hereunto aifix my signature.

LEOPOLD SCHULL- I 

